To provide a brain-directed derivative of the anti-AIDS drug AZT, a redox prodrug form of this nucleoside was synthesized. Studies in extracts of rat brain have demonstrated that this material can be acted upon by rat brain enzymes to be converted into a positively charged form, which may be locked in the brain and then release AZT itself. Preliminary studies in vivo in rats showed that this compound is transported into the brain, where it is found as the positively charged prodrug form. Studies on potential inhibitors of human immunodeficiency virus reverse transcriptase also have initiated.